Professional pesticide use ups risk of nasal woes

NEW YORK (Reuters Health) - When people think about pesticides and health, cancer and birth defects probably come to mind. But new research shows pesticide exposure may contribute to a much more common affliction: itchy, runny, stuffy noses.

"Pesticides have more potential consequences than we've considered. There are a lot of things they can contribute to," Dr. Jane A. Hoppin, of the National Institute of Environmental Health Sciences in Research Triangle, North Carolina, told Reuters Health.

Hoppin is part of a team of researchers who have been studying over 57,000 licensed pesticide applicators since 1993. They began publishing their findings in 2000. Most of the people included in the current investigation, known as the Agricultural Health Study, are farmers, while the rest are workers hired to apply pesticides to crops, seed and animals.

Past studies have linked exposure to certain pesticides with upper respiratory symptoms like wheezing, so Hoppin and her team decided to investigate whether pesticides might cause rhinitis (nasal inflammation), too.

They looked at 2,245 commercial pesticide applicators, 74 percent of whom said they'd had an episode of rhinitis in the past year. This is much higher than the rate of rhinitis seen in the general population, which tops out at around 30 percent.

Exposure to five of the 34 pesticides that the researchers included in their analysis was associated with a greater risk of rhinitis. This included two very commonly used pesticides, 2,4-D and glyphosate; 45 percent and 52 percent of the study participants reporting rhinitis had been exposed to them, respectively.

People may also use these chemicals in their homes and gardens, Hoppin noted, but they're likely to be exposed to lower concentrations, much less often, than licensed pesticide applicators.

Associations were also seen for diazinon, an insecticide banned for residential use since 2004; petroleum oil, which is often added to pesticides to enhance their stickiness; and benomyl, a rarely used fungicide.

The study only looked at a single point in time, Hoppin noted, so it couldn't show whether pesticide exposure came before rhinitis, or vice versa. Nevertheless, she added, they found that the risk of rhinitis increased with the number of days a person used petroleum oil or diazinon, which hints at a causal relationship.